This invention relates to a device for damping an oscillatory system.
Oscillatory systems are used, for example, in mechanical vibration isolation systems for audio reproducing equipment. Typically, such mechanical vibration isolation systems comprise a plurality of mounting springs which in conjunction with the mass of the equipment produce an oscillatory system having a natural frequency which is typically below 12 Hz. In order to provide some stability in the mounting, it is usual to provide some means for damping oscillation, for example a piece of plastics foam.
There are, however, a number of disadvantages associated with such damping devices. Thus, the damping device will normally reduce the degree of vibration isolation attained and will also reduce, to some extent, the effective frequency bandwidth of the isolation system. Also, there are increasing practical difficulties in designing the damping devices when the natural frequency of the oscillatory system is reduced in order to reduce coupling with other oscillatory parts of the equipment and to increase the low frequency isolation. Moreover, it is difficult to control the degree of damping in three planes of oscillation.